shill: Use system metrics headers rather than local ones.

This relies on the fact that we use quotes only for ../shill includes. So,
.. will not be included in the search path for <metrics/metrics_library.h>, for
example.

BUG=chromium-os:24729
TEST=cros_workon_make and emerge-<board> shill

Change-Id: Iff0da5817865f728d0633fb122287037507218f2
Reviewed-on: https://gerrit.chromium.org/gerrit/16271
Tested-by: Darin Petkov <petkov@chromium.org>
Reviewed-by: Paul Stewart <pstew@chromium.org>
Reviewed-by: mukesh agrawal <quiche@chromium.org>
Commit-Ready: Darin Petkov <petkov@chromium.org>
diff --git a/dns_client.cc b/dns_client.cc
index 7fdbfbe..fed71b2 100644
--- a/dns_client.cc
+++ b/dns_client.cc
@@ -17,8 +17,8 @@
 
 #include <base/stl_util-inl.h>
 
-#include <shill/shill_ares.h>
-#include <shill/shill_time.h>
+#include "shill/shill_ares.h"
+#include "shill/shill_time.h"
 
 using std::map;
 using std::set;